The invention relates to an axial plunging unit for transmitting torque within a vehicle driveline. One type of axial plunging unit includes a profiled journal with first circumferentially distributed, longitudinally extending ball grooves, a profiled sleeve with second circumferentially distributed, longitudinally extending ball grooves, as well as balls which are arranged in pairs of first and second ball grooves in identical groups. Units of this type are used in propeller shafts or sideshafts in the driveline of motor vehicles at least in those cases where only fixed joints without their own axial plunging facility are used at the shaft connections. The primary requirements are easy plungeability and the longest possible service life. The present invention is directed towards an improved axial plunging unit.